Port Louis: Mauritius' president on Sunday named veteran politician Sir Anerood Jugnauth as prime minister, after the 84-year old won a landslide victory taking nearly three-quarters of seats in parliament.

Jugnauth, a former president and prime minister, was handed his letter of appointment at a meeting at State House today, a statement from the office of President Kailash Purryag said.

Jugnauth's centre-right Alliance Lepep swept up 47 out of 62 seats in the Indian Ocean nation's parliament, after voters on Wednesday rejected the ruling party's bid to boost presidential powers.

The coalition of the outgoing ruling Labour Party (PTR) and the former opposition Mauritian Militant Movement (MMM) of ex-prime minister Paul Berenger, took just 13 seats.

Two other lawmakers from local parties on the small island of Rodrigues, some 560 kilometres to the east, usually support the government.

Debate over constitutional reform -- notably over a divisive proposal to strengthen presidential powers -- made Wednesday's poll one of the most crucial since the islands gained independence from Britain in 1968.

Jugnauth, previously prime minster between 1982-1995 and again between 2000-2003, has promised he will boost the economy.

Defeated prime minister Navinchandra Ramgoolam handed in his resignation to the president on Saturday.

The defeat was so crushing that Ramgoolam, who had wanted to run for the presidency himself, even lost his own seat that he has held for 23 years.

Had PTR-MMM won they had wanted to amend the constitution so the president would be directly elected. The largely ceremonial position is now elected by parliament.

Mauritius is one of the richest countries in Africa, a middle-income country of some 1.3 million people, with a per capita GDP of just over $9,000 (7,200 euros).

The country has had only four prime ministers in its history.

Jugnauth and Ramgoolam have alternated posts since 1982, except for a brief interlude between 2003 and 2005 when Berenger served as prime minister. Jugnauth was also president between 2003-2012.

Ramgoolam's father, Seewoosagur Ramgoolam, led the country to independence and also served as chief and prime minister.